<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >maxdb_ping</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="PHP 手册" HREF="index.html"><LINK REL="UP" TITLE="MaxDB PHP Extension" HREF="ref.maxdb.html"><LINK REL="PREVIOUS" TITLE="maxdb_param_count" HREF="function.maxdb-param-count.html"><LINK REL="NEXT" TITLE="maxdb_prepare" HREF="function.maxdb-prepare.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8"></HEAD ><BODY CLASS="refentry" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP 手册</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.maxdb-param-count.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.maxdb-prepare.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.maxdb-ping" ></A >maxdb_ping</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN111904" ></A ><P > (PECL)</P >maxdb_ping<P > (no version information, might be only in CVS)</P >maxdb->ping -- Pings a server connection, or tries to reconnect if the connection has gone down</DIV ><DIV CLASS="refsect1" ><A NAME="AEN111908" ></A ><H2 >Description</H2 ><P >Procedural style:</P >bool <B CLASS="methodname" >maxdb_ping</B > ( resource link )<BR ></BR ><P >Object oriented style (method):</P >class <B CLASS="classname" >maxdb</B > { <BR ></BR >bool <B CLASS="methodname" >ping</B > ( void )<BR ></BR >}<P > Checks whether the connection to the server is working. If it has gone down, and global option <TT CLASS="literal" >maxdb.reconnect</TT > is enabled an automatic reconnection is attempted. </P ><P > This function can be used by clients that remain idle for a long while, to check whether the server has closed the connection and reconnect if necessary. </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN111928" ></A ><H2 >Return values</H2 ><P > 如果成功则返回 <TT CLASS="constant" ><B >TRUE</B ></TT >,失败则返回 <TT CLASS="constant" ><B >FALSE</B ></TT >。 </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN111933" ></A ><H2 >Example</H2 ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN111935" ></A ><P ><B >例 1. Object oriented style</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br />$maxdb </font><font color="#007700">= new </font><font color="#0000BB">maxdb</font><font color="#007700">(</font><font color="#DD0000">"localhost"</font><font color="#007700">, </font><font color="#DD0000">"MONA"</font><font color="#007700">, </font><font color="#DD0000">"RED"</font><font color="#007700">, </font><font color="#DD0000">"DEMODB"</font><font color="#007700">);<br /><br /></font><font color="#FF8000">/* check connection */<br /></font><font color="#007700">if (</font><font color="#0000BB">maxdb_connect_errno</font><font color="#007700">()) {<br /> </font><font color="#0000BB">printf</font><font color="#007700">(</font><font color="#DD0000">"Connect failed: %s\n"</font><font color="#007700">, </font><font color="#0000BB">maxdb_connect_error</font><font color="#007700">());<br /> exit();<br />}<br /><br /></font><font color="#FF8000">/* check if server is alive */<br /></font><font color="#007700">if (</font><font color="#0000BB">$maxdb</font><font color="#007700">-></font><font color="#0000BB">ping</font><font color="#007700">()) {<br /> </font><font color="#0000BB">printf </font><font color="#007700">(</font><font color="#DD0000">"Our connection is ok!\n"</font><font color="#007700">);<br />} else {<br /> </font><font color="#0000BB">printf </font><font color="#007700">(</font><font color="#DD0000">"Error: %s\n"</font><font color="#007700">, </font><font color="#0000BB">$maxdb</font><font color="#007700">-></font><font color="#0000BB">error</font><font color="#007700">);<br />}<br /><br /></font><font color="#FF8000">/* close connection */<br /></font><font color="#0000BB">$maxdb</font><font color="#007700">-></font><font color="#0000BB">close</font><font color="#007700">();<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN111938" ></A ><P ><B >例 2. Procedural style</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br />$link </font><font color="#007700">= </font><font color="#0000BB">maxdb_connect</font><font color="#007700">(</font><font color="#DD0000">"localhost"</font><font color="#007700">, </font><font color="#DD0000">"MONA"</font><font color="#007700">, </font><font color="#DD0000">"RED"</font><font color="#007700">, </font><font color="#DD0000">"DEMODB"</font><font color="#007700">);<br /><br /></font><font color="#FF8000">/* check connection */<br /></font><font color="#007700">if (</font><font color="#0000BB">maxdb_connect_errno</font><font color="#007700">()) {<br /> </font><font color="#0000BB">printf</font><font color="#007700">(</font><font color="#DD0000">"Connect failed: %s\n"</font><font color="#007700">, </font><font color="#0000BB">maxdb_connect_error</font><font color="#007700">());<br /> exit();<br />}<br /><br /></font><font color="#FF8000">/* check if server is alive */<br /></font><font color="#007700">if (</font><font color="#0000BB">maxdb_ping</font><font color="#007700">(</font><font color="#0000BB">$link</font><font color="#007700">)) {<br /> </font><font color="#0000BB">printf </font><font color="#007700">(</font><font color="#DD0000">"Our connection is ok!\n"</font><font color="#007700">);<br />} else {<br /> </font><font color="#0000BB">printf </font><font color="#007700">(</font><font color="#DD0000">"Error: %s\n"</font><font color="#007700">, </font><font color="#0000BB">maxdb_error</font><font color="#007700">(</font><font color="#0000BB">$link</font><font color="#007700">));<br />}<br /><br /></font><font color="#FF8000">/* close connection */<br /></font><font color="#0000BB">maxdb_close</font><font color="#007700">(</font><font color="#0000BB">$link</font><font color="#007700">);<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE ><P > The above examples would produce the following output: </P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><PRE CLASS="screen" >Our connection is ok!</PRE ></TD ></TR ></TABLE ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="function.maxdb-param-count.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >起始页</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.maxdb-prepare.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >maxdb_param_count</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.maxdb.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >maxdb_prepare</TD ></TR ></TABLE ></DIV ></BODY ></HTML >